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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2011-04-13 10:31:52 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-22 08:50:00 -0700
commit165ed2c6017e420a5b640b918162b7729c5ef3ab (patch)
treed12a04c4c8e1f5e329ca11dda2244eb3b1e27821
parent6f70a0f2754aa565b1b05366e454929d4086d2a8 (diff)
downloadlinux-linaro-stable-165ed2c6017e420a5b640b918162b7729c5ef3ab.tar.gz
UBIFS: fix oops when R/O file-system is fsync'ed
commit 78530bf7f2559b317c04991b52217c1608d5a58d upstream. This patch fixes severe UBIFS bug: UBIFS oopses when we 'fsync()' an file on R/O-mounter file-system. We (the UBIFS authors) incorrectly thought that VFS would not propagate 'fsync()' down to the file-system if it is read-only, but this is not the case. It is easy to exploit this bug using the following simple perl script: use strict; use File::Sync qw(fsync sync); die "File path is not specified" if not defined $ARGV[0]; my $path = $ARGV[0]; open FILE, "<", "$path" or die "Cannot open $path: $!"; fsync(\*FILE) or die "cannot fsync $path: $!"; close FILE or die "Cannot close $path: $!"; Thanks to Reuben Dowle <Reuben.Dowle@navico.com> for reporting about this issue. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Reported-by: Reuben Dowle <Reuben.Dowle@navico.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/ubifs/file.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 16a6444330ec..98ae58cdbd41 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1311,6 +1311,9 @@ int ubifs_fsync(struct file *file, struct dentry *dentry, int datasync)
dbg_gen("syncing inode %lu", inode->i_ino);
+ if (inode->i_sb->s_flags & MS_RDONLY)
+ return 0;
+
/*
* VFS has already synchronized dirty pages for this inode. Synchronize
* the inode unless this is a 'datasync()' call.